Just recently, my tank has had a major algae outbreak. I've never had much of an algae problem before because my otos have always taken care of it. But lately, they seem to only want to eat zucchini instead of the algae. It also looks like they might have lost a little weight.

I have a 20 gallon long, moderately planted with a gourami, tetra, african dwarf frogs, and 3 otos. The tank has been running since last August. The otos have been in my tank since September. I know their tricky fish, but I've never had an issue with them.

A couple months ago, I had a big problem with that nasty black "beard" algae (otos won't eat it), but finally got it under control. Within the last couple weeks I've noticed that everything is getting coated with brown diatoms and my glass has green spot algae. Weird because those are the types of algae otos eat, but mine are always latched onto the veggies in the tank. Now the gross black algae looks like it might attempt a comeback and I really don't want it to. My plants are looking awful due to the algae.

What can I do? Should I stop putting veggies in the tank? Do I not have enough otos for my size of tank? Any thoughts on this at all? Thanks!

Otos normally eat only common green algae and diatoms (brown algae). They won't do much with the green spot, at least mine don't. But they should handle the brown easily.

I would suggest stopping the "treats" in an attempt to get them back to their natural diet. If there is brown algae, they won't starve. But keep an eye on them.

As for the algae problem: algae occurs when light is available along with nutrients. Live plants will out-compete them, but if the nutrients are depleted, plants can't photosynthesize and any light beyond that point will only cause algae.

How long is the light on daily, and what type [be specific]? Are you adding any plant fertilizer? What plant species do you have?

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.[unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]